Mumps is a contagious disease caused by the mumps virus. It spreads through the air when an infected person coughs or sneezes. Items used by an infected person, such as cups or phones, can also be contaminated with the virus, which may spread to others if those items are shared. In addition, the virus may spread when someone with mumps touches items or surfaces without washing their hands and someone else then touches the same surface and rubs their mouth or nose.

Up to half of people who get mumps have very mild or no symptoms, and therefore do not know they were infected. The most common symptoms include: fever, headache, muscle aches, tiredness, loss of appetite and swollen and tender salivary glands under the ears on one or both sides (parotitis).

Symptoms typically appear 16-18 days after infection, but this period can range from 12-25 days.

Mumps is best known for the swelling of the cheeks and jaw, which is a result of swelling of the salivary glands. People who show symptoms usually recover after a week or two, but mumps can occasionally cause serious complications.

The most common complication is swelling of the testicles in males who have reached puberty. Other rare complications include:

Inflammation of the brain and/or tissue covering the brain and spinal cord (encephalitis/meningitis)

Inflammation of the ovaries and/or breasts in females who have reached puberty

Deafness

According to the United States Centers for Disease Control, Mumps vaccine is the best way to prevent mumps. This vaccine is included in the combination measles-mumps-rubella (MMR) and measles-mumps-rubella-varicella (MMRV) vaccines. Two doses of mumps vaccine are 88% effective at preventing the disease; one dose is 78% effective. There are some strains of the virus that are not covered by the vaccine.